Add List.insert.

tools/dom/src/WrappedList.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of dart.dom.html;
 
 /**
  * A list which just wraps another list, for either intercepting list calls or
  * retyping the list (for example, from List<A> to List<B> where B extends A).
  */
@@ skipping 91 matching lines @@
   void addLast(E value) { _list.add(value); }
 
   Iterable<E> get reversed => _list.reversed;
 
   void sort([int compare(E a, E b)]) { _list.sort(compare); }
 
   int indexOf(E element, [int start = 0]) => _list.indexOf(element, start);
 
   int lastIndexOf(E element, [int start]) => _list.lastIndexOf(element, start);
 
+  void insert(int index, E element) => _list.insert(index, element);
+
   E removeAt(int index) => _list.removeAt(index);
 
   E removeLast() => _list.removeLast();
 
   List<E> getRange(int start, int length) => _list.getRange(start, length);
 
   void setRange(int start, int length, List<E> from, [int startFrom]) {
     _list.setRange(start, length, from, startFrom);
   }
 
@@ skipping 13 matching lines @@
   Iterator _iterator;
 
   _WrappedIterator(this._iterator);
 
   bool moveNext() {
     return _iterator.moveNext();
   }
 
   E get current => _iterator.current;
 }